Apparatus for suppressing vibration in a helical-rotor axial-flow compressor supplied with sealing water

ABSTRACT

A helical-rotor axial flow compressor has a sealing-water inlet extending through its casing. A water-supply pipe is connected to said inlet. A gas-supply pipe is tapped into said water-supply pipe and is connected to a source of gas under a pressure higher than that of the water in the water-supply pipe. This suppresses the vibration otherwise resulting from the stopping or shutting off of the water stream entering into the casing, by the passage of the rotor lands.

United States Patent Dennis J. I-Ianick Elizabeth, Pa.

Nov. 27, 1968 Apr. 20, 1971 United States Steel Corporation Inventor App]. No. Filed Patented Assignee APPARATUS FOR SUPPRESSING VIBRATION IN A HELICAL-ROTOR AXIAL-FLOW COMPRESSOR SUPPLIED WITH SEALING WATER 2 Claims, 2 Drawing Figs.

418/99 F04c 17/04 Field of Search 230/ 120,

3,138,320 6/1964 Schibbye 230/143 3,132,839 5/1964 Haekal 415/1 3,129,877 4/1964 Nilsson et a1. 230/143 1,273,900 7/1918 Miller 230/120 1,355,231 10/1920 Kien 230/120 1,737,870 12/1929 Telfer 103/111 2,549,819 4/1951 Kane 230/209 3,237,565 3/1966 I-Iartland 103/97 FOREIGN PATENTS 620,845 2/1957 Canada 253/1 17 929,360 6/1955 Germany 253/1 17 Primary ExaminerHenry F. Raduazo Attorney-Donald S. Ferito ABSTRACT: A helical-rotor axial flow compressor has a sealing water inlet extending through its casing. A watersupply pipe is connected to said inlet. A gas-supply pipe is tapped into said water-supply pipe and is connected to a source of gas under a pressure higher than that of the water in the water-supply pipe. This suppresses the vibration otherwise resulting from the stopping or shutting off of the water stream entering into the casing, by the passage of the rotor lands.

- PATENTED APRZO um nvvewron DENNIS .1. HAN/CK I Arromgy APPARATUS FOR SUPPRESSING VIBRATION IN A I-IELICAL-ROTOR AXIAL-FLOW COMPRESSOR SUPPLIED WITH SEALING WATER This invention relates to the suppression of vibration and noise resulting from the introduction of a stream of sealing water into the casing of a helical-rotor axial flow compressor.

BACKGROUND OF THE INVENTION Helical-rotor axial flow compressors of the type shown in U.S. Pat. Nos. 2,174,522 and 2,243,874 have been used in compressing coke oven gases. It has been the practice, in such use, to introduce sealing water into the gas inlet of the compressor. This has the objectionable effect of condensing naphthalene vapors in the compressor inlet andaffecting'gas flow. To avoid this condition the point of sealing-water introduction was changed from the gas inlet to a point on the interior of the casing by drilling through the wall thereof. This eliminated naphthalene formation in the compressor inlet but caused an intolerable vibration and noise resulting from water hammer set up by the stopping or shutting off of the stream of entering water at high frequency by the rotor lands as they wiped across the inner end of the drilled water-inlet passage.

BRIEF SUMMARY OF THE INVENTION l have discovered that the aforementioned noise and vibration may be reduced to an unobjectionable level simply by bleeding into the water stream entering the compressor casing a small amount of gas under pressure greater than that of the water. The gas may conveniently be derived from the compressor outlet and brought to the water-supply pipe by a side connection.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment. In the drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic side elevation, and FIG. 2 is a partial section through the compressor casing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to the drawing a helical-rotor axial flow compression has twin helical rotors lll joumaled in its casing 12 which, on being driven, tend to move gas from an inlet 13 at one end of the casing to the outlet 14 at the other end. Sealing water is introduced through a passage 16 in the casing wall adjacent the inlet end by a pipe. .15 connected to a suitable water source at a pressure of about 40 p.s.i.a.

As shown in FIG. 2, the stream of water entering the casing 12 through pipe 15 and passage 16 is shut off at high frequency by the lands of one of the rotors 11 when the latter are driven at high speed. To suppress the resulting noise and vibration, i.e. water hammer, I tap a small side-connection pipe 17 from outlet 14 into pipe IS. When the compressor 10 is used to move coke oven gas, the pressure at the inlet I3 is slightly below atmospheric, i.e. 13.5 p.s.i.a., and the pressure at the outlet 14 is about 53 p.s.i.a. Gas will therefore flow from the outlet through pipe 17 and into the water stream in pipe 15. The effect of this arrangement is to reduce materially the noise and vibration created by the compressor to an easily tolerable level. Any gas available may be used, in addition to coke oven gas, and the effect is the same. Bleeding gas into the sealing-water stream evidently forms bubbles therein which afford a cushion when the water flow is momentarily stopped and thus prevents the generation of water hammer.

It will be apparent that my invention provides an unusually simple, inexpensive and maintenance-free solution to a troublesome condition in compressor operation which defied several other attempts to overcome it.

Although I have disclosed herein the preferred embodiment of my inyention, I intend to cover as well any change or modr rcation therein which may be made without departing from the spirit and scope of the invention as set forth in the claims.

lclaim:

I. The combination with a helical-rotor axial flow compressor with a housing thereabout, said housing having a pair of cooperating helical rotors therein and a sealing water supply passage extending thereinto, the inner end of said passage intersecting the periphery of the path of travel of one of said helical rotors whereby said inner end of said passage is periodically substantially shut off by the lands of said one of said helical rotors, of a water pipe connected to said passage, a source of gas under pressure greater than that of the water in said pipe, and a gas-supply pipe connected to said water pipe and to said source whereby a mixture of water and gas is supplied periodically to said passage suppressing vibration and noise in the compressor.

2. Apparatus as defined by claim 1 in which said source is the outlet of said compressor. 

1. The combination with a helical-rotor axial flow compressor with a housing thereabout, said housing having a pair of cooperating helical rotors therein and a sealing water supply passage extending thereinto, the inner end of said passage intersecting the periphery of the path of travel of one of said helical rotors whereby said inner end of said passage is periodically substantially shut off by the lands of said one of said helical rotors, of a water pipe connected to said passage, a source of gas under pressure greater than that of the water in said pipe, and a gas-supply pipe connected to said water pipe and to said source whereby a mixture of water and gas is supplied periodically to said passage suppressing vibration and noise in the compressor.
 2. Apparatus as defined by claim 1 in which said source is the outlet of said compressor. 